Gliederung

Objective

To study the time-course of hemangiogenesis versus lymphangiogenesis in the cornea after a temporary inflammatory insult. This might be helpful in the timing of corneal transplantation in high-risk eyes.

Methods

The mouse model of suture-induced inflammatory corneal neovascularization was used: After placement of three interrupted 11-0 sutures into the corneal stroma for 14 days, corneas were excised 2, 5 and 7 days as well as 1, 2, 3, 6 and 9 months after surgery. Hem- and lymphangiogensis was quantified using double immunohistochemistry of corneal flatmounts with CD31 as panendothelial and LYVE-1 as lymphatic endothelial marker.

Results

Both blood and lymphatic vessels grew into the cornea as early as day 2. The outgrowth was initially paralell. Hem- and lymphvascularization peaked around day 21 and 28, respectively. Thereafter both vessel types started to regress. Regression of lymphatic vessels started earlier and was more pronounced than that of blood vessels. Whereas at 6 and 9 months (partly) perfused blood vessels and (non-perfused) ghost vessels could still be observed, there were no LYVE-1+ vessels detectable beyond 6 months after inflammation.

Conclusions

After a temporary inflammatory insult to the cornea, there is initially parallel outgrowth of both blood and lymphatic vessels. But thereafter, lymphatic vessels regress earlier and more pronounced than blood vessels and are completely regressed by 6 months. Earlier regression of lymph versus pathologic corneal blood vessels suggests that corneal graft survival in high-risk eyes is better after an interval of at least six months following an inflammatory insult.